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SSR and Holding Current

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kolbep:
Hi All.
Just a quick one.
I have several led string lights (230v 7w per 20m string) = 0.031mA
IIRC the strings have 160 leds in Series with a resistor, which is in parallel with another 60 leds with their resistor.

I am trying to run them with Omron G3MB-202P Solid State Relays (1 solid state relay per string). The SSR's are controlled with Shift Registers on an Arduino.

I am having a problem where the LED strings where they are running dim, sometimes don't light up, or light up, then go dim immediately afterwards

The Omron SSR's are rated for 0.1A to 2A current. I presume the 0.1A is the minimum (holding) current.

My Arduino program does not pulse the SSR's, instead it keeps the power on to the SSR the whole time the light chain is meant to be on (i.e any time from 250ms upwards). Does that mean that I do not need to worry about the 0.1A holding current (because the SSR does not need to self latch)?

If I need to worry about the holding current, then I will need to put a dummy load equivalent to 2300R, 23W (that will probably need to be normal lightbulbs, because large resistors will get a bit hot.

If it is not the Holding Current causing the problems, then could it be that I am trying to run the LED strings with a Triac (and as there is no rectifier, the LEDS are only drawing on the forward cycle). If that is the case, then I will probably need a bridge rectifier on each string.

It also seems to be more problems with the White-Flash Strings. They are similar construction, but every 5th LED flashes at it's own rate.

Thanks for any suggestions.

P

NiHaoMike:
Try using a series combination of a resistor and capacitor as the minimum load, good starting point would be X rated 1uF and 100 ohm, 2W.

kolbep:
Thanks,
Let me scrounge through my boards, and see if I can find some to try that out.

P

kolbep:
Just another question,
the voltage for the 1uF Class X Capacitor,
What voltage should that be, with our Voltage in South Africa being RMS 240v or should it be based on  the peak of 340v?,

NiHaoMike:
Every X rated capacitor I have seen is rated to at least 250V RMS, that's a nominal rating and will work on 240V.

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